A torque fluctuation absorbing apparatus is disposed, for example, in a power transmission path between an engine and a reduction gear unit, so as to absorb (suppress) fluctuations in torque between the engine and the reduction gear unit. Among the torque fluctuation absorbing apparatuses is one that comprises a damper section (mechanism) which undergoes torsional motion when subjected to a fluctuation in torque and absorbs (suppresses) the fluctuation in torque through elastic force exerted by a coil spring disposed between a drive plate and a driven plate, and a hysteresis section (mechanism) which absorbs (suppresses) the fluctuations in torque by means of frictional force (hysteresis torque) exerted by a thrust member (frictional member) disposed between the drive plate and the driven plate. In some of the torque fluctuation absorbing apparatuses of the prior art, the hysteresis section (mechanism) absorbs sudden fluctuations in torque by generating a great frictional resistance when the drive plate and the driven plate rotate relative to each other.
For example, Patent Document 1 discloses a torque fluctuation absorbing apparatus that absorbs sudden fluctuations in torque when the drive plate and the driven plate rotate relative to each other, by increasing the pressure of a viscous fluid contained in a space between a pair of L-shaped thrust plates which are unable to rotate relative to the driven disk, so as to put the thrust plates into pressed contact with the driven disk, thereby generating a sliding resistance.
Patent Document 2 discloses a torque fluctuation absorbing apparatus that has a tapered force conversion section, where a wedge-shaped portion is driven to slide into a space between the tapered portion and a cylindrical portion, so as to generate a load that presses against the cylindrical portion disposed on an inner circumference and an outer circumference, thereby forcing a frictional member against the cylindrical portion by means of the load and generating frictional resistance (braking force).
[Patent Document 1]
    Japanese Unexamined Kokai Patent Publication No. 6-147273A[Patent Document 2]    German Patent Publication No. 10343063A (FIGS. 15-17)